After two debates, one presidential and one vice presidential, we can fairly conclude that Barack Obama and Joe Biden are happy warriors.

They just smile and smile and smile.

Whereas Obama’s smile during his debate with Mitt Romney seemed to be an afterthought, proffered as recompense to relieve the strain of his lackluster performance, Biden’s was an Uzi. From the time he sat down next to Paul Ryan, he was locked and loaded with the pearliest chompers since Matt Dillon donned horse veneers to impress Cameron “There’s Something About Mary” Diaz.

No matter what Ryan said (except when he told a personal story), Biden smiled. Like the Cheshire cat, he smiled. Like an Ultra Brite model, he smiled. Like someone trying to seem friendly, bemused, stunned to hear such malarkey from his debate opponent, fill-in-the-blank, he smiled. But Biden’s was no friendly smile. It looked like one, otherwise known as acting, but it was no more sincere than Biden’s repeated references to Ryan as “my friend.”

It was a tactical weapon intended to intimidate and out-psych his wonky opponent.

As we all learn, usually painfully, a smile isn’t always a smile. The difference between a smile and a grimace, after all, is a matter of a few muscles. Or as Shakespeare had Hamlet say: “That one may smile, and smile, and be a villain.”

No, I’m not calling Biden a villain, but when someone employs a smile with purpose, as he obviously did, there’s good cause to examine the behavior more closely. What did he intend? What impression was he hoping to make? What was the effect on his audience?

Post-debate commentary has included the likelihood that Democrats, deflated since Sub-Obama’s encounter with Uber-Romney, saw Biden as a mirthful wonk-slayer. A Goliath in years and stature, he slew young David from Accounting. Which is, of course, not the way the story is supposed to go.

Non-Democrats, including Republicans and independents, likely saw Biden as dismissive, rude and unnecessarily condescending. A man confident of his facts doesn’t have to deflect a weak argument with a sneer or a smile. A senior statesman can afford to be gracious, especially if he believes the facts are on his side.

To receive a warm smile is its own reward. To be on the receiving end of an insincere smile, or one that doesn’t fit the message being delivered, is psychological trickery. Think of Nurse Ratched in “One Flew Over the Cuckoo’s Nest.” She smiled even as she delivered psyche-crushing information. The disconnect between what her victims were seeing and what they were hearing and feeling was torturous. Similarly, the teacher who smiles and says “Johnny made a bad choice” is confusing and potentially enraging.

Finally, a politician who smiles while trying to take you down may be a pro, but he’s no friend.

“Who do you trust?” Biden asked Americans as he looked directly into the camera.